


Dustfall

by AmandaDBone



Category: Sherlock (TV)
Genre: Alpha!John, Alpha/Beta/Omega Dynamics, Alpha/Omega, Consent Issues, Dubious Consent, F/M, First Time, John Watson/Molly Hooper - Freeform, Knotting, M/M, Mating Cycles/In Heat, Omega!Lestrade, Omega!Sherlock, Omegaverse, Tentacles, a handful of OCs, alpha!John/omega!Sherlock - Freeform, alpha!Molly, alpha!Mrs. Hudson, everybody is angry all the time, except when they're turned on, minor Lestrade/Mrs. Hudson, one-sided John/Lestrade, some violence
Language: English
Status: Completed
Published: 2013-12-02
Updated: 2013-12-02
Packaged: 2018-01-03 07:14:57
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 19,235
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1067577
Author URL: https://archiveofourown.org/users/AmandaDBone/pseuds/AmandaDBone
Summary: <blockquote class="userstuff">
              <p><i>"I have a friend who says the government's trying to cover it all up. He says that in China people've already started changing, you know, </i>mutating<i>, developing new organs and stuff. They don't want people in a panic, he says. You think it could be true?"</i></p><p> </p><p>There are no alphas and no omegas — not until maroon dust falls from the sky and changes the world. Sherlock and John treat their biological changes with a medicine of denial and avoidance, very nearly destroying themselves in the process.</p>
            </blockquote>





	Dustfall

**Author's Note:**

  * Translation into Polski available: [Pył z nieba- TŁUMACZENIE](https://archiveofourown.org/works/3652764) by [Toootie](https://archiveofourown.org/users/Toootie/pseuds/Toootie)



> HERE COMES A LOT OF WORDS.
> 
> First of all, a MASSIVE thank you to Vertiga and Fireofangels for beta-reading; without them I would have a SPAG mess with random words just thrown in or missing, and I'd still be pulling my hair out over a certain scene or two. It's thanks to them this is done and legible. All errors, inconsistencies, or just general sloppiness that remain are my own.
> 
> I also recommend not trying to write around a cat. It does not work well.
> 
> Please note that the endgame pairing here is John/Sherlock. Other pairings that appear do not feature heavily and are not the focus here.
> 
> This story also delves repeatedly into consent issues that Omegaverse fic often brings up. Although no fully non-consensual sex happens in the story itself, it's alluded to, and sex is had while characters' ability to consent to sex properly is compromised. If dub-con might be a problem for you, you may want to turn back.

The dust was first spotted in the sky though a telescope in October, but it wasn't until a bitingly cold November night that it was visible in London.

John didn't notice it himself, at first; by the time night had fallen and the dust was at its most visible, he was seated in the back of a taxi, Sherlock ruminating on his latest case across from him. John left him to it, watching the city's scenery go by, and it wasn't long before he noticed a pattern of pedestrians craning their necks to stare at the sky.

It was impossible to see from the cab, and although some seemed rooted in place and were open-mouthed with wonder, no one seemed to be in a particular panic. Curiosity dug its claws into him, though, and as soon as he had paid the cabbie, he joined Sherlock on the pavement, looking up.

"Is it some kind of smog, do you think?" he asked, squinting in the hopes of making what he was seeing clearer. He could see no stars, but the dust's haze was almost sparkling, like it sought to replace them. "Some sort of... pollution?"

"Not likely. It's reflecting too much light — and it's purple."

John thought it looked rather red to him, but he held his tongue.

"It's maroon," Mrs. Hudson said from the door, cradling a cup of tea and glancing up as though the glittering sky was old news. "It's been in the news for weeks; it's all over the telly now. Nobody seems to know what it is, even those scientists who study outer space — the astrophysicists."

"Has it really?" John asked, tearing his eyes away from the heavens to follow Sherlock inside.

"Oh, yes. I expect you boys have been a bit too busy to notice, though."

"Boring and irrelevant to our case," Sherlock decided, heading directly for 221B where, John figured, he would no doubt assume his usual spot stretched out across the sofa, and remain there until he next saw fit to run around looking for their thief.

"It's been getting lower and lower," Mrs. Hudson stage-whispered, as though not to disturb Sherlock's thoughts with mundane topics like sparkling maroon weather phenomena. "It's all over the world now. Mrs. Turner has a nephew who thinks it's from aliens."

John huffed a laugh at that, and bade Mrs. Hudson goodnight.

* * *

When the rains came, they carried the dust down with them. Umbrellas became a necessity; without them, the watery sludge dripped into eyes and matted up hair, even made its way into noses and onto tongues, where it stung bitterly. Many, murmuring about toxins and fearing the unknown, remained indoors, waiting for a soothing reassurance from the news that it was all harmless. John had no such option, with Sherlock carting him around after a thief who turned out to be a murderer. His trousers and jumper were thoroughly stained with purplish mud in minutes, but he hardly had a moment to mourn their loss until their suspect was cuffed, with Sherlock rattling off all the incriminating evidence.

He noted that it had dried slightly on his face, and there it became tacky and stuck to his skin. It had no particular odour, and where it was wet it ran off him and soaked into fabrics like normal rainwater.

He couldn't be sure if the feeling that his skin was humming was abnormal or not. It could have been adrenaline, he thought. He decided not to worry about it.

* * *

Once sufficiently dry, the sticky wine-coloured mush became dust again. Even as people, some in Hazmat suits, came to clear it off the streets, it kicked up around John's ankles, following him in puffs as he walked to work. It settled on walls, in the cracks in the pavement, the creases of his palms — he even found himself coughing out a small cloud, wincing at the burn of it.

The patients at the surgery fared little better. Only a handful of them seemed to have the usual set of colds and infections; the rest were watery-eyed, jumpy, and somewhere between cautiously worried and manic with a fear that overrode whatever other worries they'd come in for. Worse still was that not a one of them could describe what was wrong, only that they knew something felt _different_.

"Different how?" John asked, for the fifteenth time that day. "Are you in any pain or discomfort? Feverish? Any abnormal lumps, any bruising?"

Ms. Elms gave him a helpless look and shrugged. She had a spot of colour on her cheek, and he wasn't sure if it was make-up or the dust.

He sighed. "I'm afraid that unless we can pinpoint what, exactly, feels different, I've no idea where to begin."

She looked down at his desk, and then back up at him, setting her shoulders and tipping up her chin. "I feel empty."

There! That was getting them somewhere. "Empty how? And where?"

She made a sweeping motion with her hand down her front, her fingers hovering just over her groin. "Like I'm hungry, but not in my stomach. Like I...." She trailed off, her shoulders slumping again.

John waited, trying to ignore the buzzing feeling inside his own head.

Ms. Elms swallowed thickly, averting her eyes. "Like I want sex. Need it, even. Badly."

John's heart dropped, and he struggled to keep his voice even, clearing his throat twice before he was confident his voice would be even. "Well, I'm afraid that isn't exactly my area of expertise; you may be better off seeing a therapist. If you'd like, I can—"

"But it's not like that," she pleaded, leaning forward and resting her hand on her thigh, dangerously close to her supposed emptiness. "It's constant, and physical, and it— I've never been like this before. It— it all started when it rained the other day. I got some of that red stuff in my eye, a lot of it, actually, and I think some got in my mouth. Do you think that could be it?"

John spent the rest of her appointment trying to convince her that her urges were normal, and to talk to someone else about it. She agreed, reluctantly, and John's next patient stuttered and could not bring himself to describe how he felt different at all.

* * *

"It's only a fever," Sherlock protested through gritted teeth, swatting away John's hands. "I'm not a child."

"Funny, you'd never know from the way you act." John grabbed Sherlock's wrist, checking his pulse as best he could under the circumstances. "This is more than a fever. Be honest, now, what other symptoms do you have?"

"None," Sherlock insisted. He jerked his hand away, curling up and facing the back of the sofa. "If you'd just let me rest, I could be done with it."

John frowned. "You never _rest_. You recharge and you think, but you don't rest."

Sherlock closed his eyes, pressing his sweating forehead against the sofa cushions. "Even I sleep."

"Just last week you claimed you solve problems in your dreams," John said, taking in Sherlock's position. Under any other circumstances he'd have accepted his behaviour as his usual petulance, but there was a desperate tone to his protests that he couldn't ignore, as a doctor or as his friend. With his knees tucked up and his forearms almost casually crossed over his middle, John couldn't help but think of some of the patients he'd been seeing. Increasingly, the men had begun reporting pain low in their abdomens, some of them even describing it as being torn open.

Some others, of course, had refused to say where it was at all, demanding he "just do something" about it. Of course Sherlock wouldn't even be able to muster up that much of a request for help.

Gently, John put a hand on his back, near his spine and below his kidneys. "Anything feel odd here?"

"You're touching me."

John ignored him. "Any pain?"

"No."

"Right." John stepped away, deciding to let Sherlock wallow in his own misery. If he wanted to stoically bear the pain on his own, John would let him.

A few minutes later, he set a glass of water and some paracetamol on the table. Sherlock didn't budge, and John carefully pretended not to notice when the pills disappeared.

* * *

"I have a friend who says the government's trying to cover it all up. He says that in China people've already started changing, you know, _mutating_ , developing new organs and stuff. They don't want people in a panic, he says. You think it could be true?"

John rubbed at his temple and tried to determine the most diplomatic response. Mr. Daniels was young and energetic, though John supposed that without the damper of a mysterious, wide-spread pseudo-illness he might have been even more lively. "There have been a lot of rumours about what the, ah, dust might do. I'll admit that's a new one, though."

Mr. Daniels leaned forward, beckoning him closer. John indulged him, leaning in conspiratorially. "Thing is, I've had this terrible pain, and a fever, and now it seems like something's... different, you know?"

"Different how?" came out almost automatically.

His patient flushed then, leaning back. "Well, you know, different. Like feeling parts of your body you didn't know you had, yeah? Only now I'm not so sure I did have them before."

John resisted the urge to roll his eyes. Mr. Daniels wasn't the first to see him with a conspiracy theory, after all, and if he was having the same symptoms Sherlock was, he likely had something legitimately wrong with him. "What sort of pain is it?"

"Like a tearing," he replied, which John had heard before, and then: "In my arse."

He hadn't heard that. He had suspected it, after seeing a dozen men gesture vaguely at their lower backs and get dodgy about answering specifics, but none of them would come out and say so, and some of them seemed so bewildered and frightened he couldn't be sure. "In your...?"

"My rec-tum," Mr. Daniels said, enunciating each syllable clearly. "I, er, I poked around a bit, and I've never done that before, I swear, but something didn't feel right."

It might have been an over-active imagination, or it might have just been that Mr. Daniels had found his prostate and had been too embarrassed and anxious to realise it. On the other hand, John had had a complete dearth of information about what was going on since the sky had dropped indigo rains on them, and he was in no position to work off assumptions.

It had taken some persuasion to convince Mr. Daniels that he was completely safe in removing his pants in John's office, and that John was only looking out for the best interests of his health. A dab of medical grade lubricant later, and John was in the routine for a normal prostate check when his patient choked out, "Wait, stop. It's... it's deeper than that."

It took switching to his middle finger to find what he was looking for: a spot just a bit beyond his patient’s prostate, slightly smoother and more rubbery-feeling than the rest of him.

"That's it, oh god, that's it. I'm a mutant, aren't I?"

"You're fine," John said, trying to sound soothing but only coming out distracted. He racked his mind for an explanation, anything that could result in an abnormality in a man's rectal walls, a lesion of some sort, or—

Unthinkingly, he pressed in just a little, and the flesh under his fingertip gave way, then clamped down on him. "Jesus," Mr. Daniels gasped, writhing on the examining table, "God, what _is_ that?"

John couldn't reply; his head was swimming. He started when a hand — Mr. Daniels, reaching back — grasped his forearm, and couldn't help the way his jaw went slack as he realised he was trying to pull him _in_.

It took considerable effort, both on his own will and on Mr. Daniels, to remove his hand, and the foggy feeling in his mind lasted through fumbling apologies, a hazy line-up of patients, and until he feel asleep that night.

* * *

The papers had begun to acknowledge that certain people were experiencing extreme biological changes, and that seemed to be Sherlock's cue to do the same. Naturally, he chose the morgue for his own examinations; under normal circumstances, John would have let him at it on his own, but with the way he stumbled now and then and still shivered from a fever that he insisted had come down, he couldn't in good conscience leave Molly to deal with him on her own.

They kept their distance as Sherlock examined his corpse — a "fresh one", as he demanded — from ear to toe, poking and squeezing in every intimate spot he could.

"Does he seem, I don't know, sort of... different, to you?" Molly asked, not bothering to tear her eyes away from the mad detective.

"He's always been different." It wasn't a real answer, of course, but what could John say? He hadn't the faintest idea of what was going on, and when he tried to connect the memory of what had happened at the surgery to Sherlock's symptoms, it was like his cognitive abilities just shut down.

"What do you think he'll find?"

There was a tremulous note to her voice, and John looked at her, really looked, trying to see her as Sherlock would. She was shining, sweating, her hair dark with it at her scalp but clean at the ends. Her bottom lip was red and bruised, but her top smooth and pink. Her fingers clenched and unclenched almost rhythmically, and she kept tugging at her skirt.

She smelled strange. He couldn't place it, but something told him it wasn't a perfume. He didn't like it.

She'd lost weight since he'd last seen her, and it wasn't diet and exercise showing; her skin had a slightly sallow tone to it, the darkness under her eyes pulling at her cheekbones unfavourably. It wasn't an unhealthy loss, not yet, but John reminded himself to check on her later, to remind her to eat even through the pain he was certain she was suffering, just as Sherlock was.

A small movement caught his eye, and he had only a moment to catch sight of a small, fleshy protrusion under the edge of her skirt, not unlike a smooth finger, wriggling in his direction. It retreated quickly, and he looked up to catch Molly's eye. Her jaw tightened, and she said nothing.

"I don't know," he finally answered, fixing his gaze back on Sherlock, who had three fingers inside the corpse's vagina. He tried not to imagine anything feeling back at him.

* * *

For all the weight of the binder Dr. Cobb dropped on John's desk, it didn't seem to contain all that much concrete information; a third of the content of each page was conjecture and theory, and much of the rest was what Dr. Cobb was calling "damage control."

"Some quacks are trying to classify the changes by the emotional responses people are having — they say the aggression and submission are the most significant aspects of it — but as we're in the business of actually treating bodies, we're going with the degree of physical change." She flipped to a page that had a diagram of a female body, with a few unfamiliar additions. "This is Type I: the ones who develop new organs. We treat the pain, assess development according to what's been seen so far, and if they're concerned, you can prescribe something to suppress the libido. They have a list of options here. _Do not_ recommend removal of anything; no one's really sure how to do it safely yet. For the most part, we're just going to be telling them we don't know much and we're doing the best we can, got it?"

John nodded, his eyes skimming the page rapidly. Here and there phrases caught his attention: "prehensile intra-vaginal appendages," "sensitivity to certain smells," "difficulty focusing when sexually stimulated." It was certainly looking to be an interesting read, at least.

"Type II is the subtler one," Dr. Cobb went on, flipping a few pages for him. "There aren't any whole organs appearing, but possibly new functions to existing ones. It might not look like much to worry about as of yet, but for all we know it could get worse; try to allay their fears without dismissing their concerns completely, all right? I'm hoping we can get people to come back when we know more. For now, there's not much we can do. We're going to be even less popular then usual, but don't get creative with them."

"Got it," John replied, pulling the binder toward him.

"Good. You've got a half hour to read through that before your first patient." Dr. Cobb stood up, her greying hair swaying behind her, and went to the door. Halfway out, she paused, turning back toward him. "Oh, and John?"

He looked up, raising his eyebrows and waiting.

She just watched him for a moment, not entirely unlike Sherlock, before she spoke. "If you start experiencing any of the symptoms in there, we have to know. That purple dust might've caused this, but we can't risk the possibility of it getting any worse through exposure. Got it?"

"Of course." John smiled; if it looked a bit strained, well, the whole situation was stressful for the lot of them.

As soon as the door was closed behind her, he let his shoulders sag and began reading, starting with the Type I male section.

* * *

"I know he's only really interested in the murders and weird thefts," Lestrade said, keeping his voice low, "but it's all started to go completely mad with the sexual crimes unit. Those sorts of cases have never been easy, but now... well, you know."

John did; things had got bad enough that the papers and news programs couldn't ignore or downplay them anymore. Reports of rape had more than doubled since the dust had fallen, and it was clear that law enforcement had no idea how to sort it all out. They weren't just beyond their normal numbers, either; from what John could tell, and from what he'd gleaned from Lestrade, the reports were often confused on both ends, with some of the victims claiming to have felt drugged but clear-headed, others saying one moment that they'd consented and the next that they hadn't meant to or hadn't at all, and an unprecedented number of men and women coming forward and confessing, often with the same mix of answers the victims gave.

It was deeply unsettling, but John was having trouble feeling that, with the way Lestrade was leaning in toward him. He just smelled so _good_ , and John couldn't remember liking him so much before.

He couldn't remember ever feeling so uncomfortably aroused around him, either.

With a great force of will, he stepped away under the pretence of seeing what Sherlock was up to. No more than the usual, of course: two bodies, both older men, found inside a flat that belonged to neither of them. One of them was naked, and it was over that man that Sherlock crouched, his gloved hands holding up one of he corpse's hands as he examined its fingernails.

"Any progress?" John asked, only slightly interested. He tried not to breathe deeply; the men hadn't been dead long, from what he could tell, but they smelled unusually unpleasant.

"Plenty," Sherlock said, then remained quiet for another moment, finishing his inspection of the thumb nail. He set it down over the man's chest, as he'd found it, and gestured to the body's groin. "Look. What do you make of this?"

John spared a moment's regret that it wasn't the first time Sherlock had told him to look closely at a dead man's penis, then crouched down beside him. Strangely, at that level the smell seemed much more bearable.

The man was, for the most part, unremarkable; he'd been getting on in years and in weight, and some parts of him had begun to sag prematurely. His cock, however, was another story: although it largely looked like any man's might, the base of it, just above his testicles, was round and swollen, still dark with blood.

"Type II?" John suggested, remembering the diagrams. "You think someone's targeting people who've changed?"

"No, obviously not. He's naked, and look at the state of him; he was obviously aroused when he died, and either anticipating or already participating in sex. There's blood under his fingernails, and yet the man who strangled him is over there, completely scratch-free. Whoever murdered our second man was likely under attack from our Type II here, or helping them to escape."

John looked over at the second corpse, wondering what they'd find under his clothes. "So rape, then?"

"Or very rough sex, yes."

"How does the second body figure in? Why would a rape victim kill their rescuer?"

"He wasn't there to rescue them," Sherlock said, standing and stepping over the naked body, completely nonchalant. "Look at him: his belt's unbuckled, his fly undone. The angle of his head suggests the blow came from underneath him, and the blood on his hands didn't come from strangling anybody. He just wanted in on the action."

John let out a breath he hadn't realised he'd been holding in, and looked over at Lestrade. It seemed he'd get Sherlock involved in the more complicated sex crimes after all.

* * *

Had he not been paying attention, John might have thought Sherlock was in the middle of another one of his between-case strops. But he was paying attention, and intently, too; it seemed impossible to ignore the way Sherlock fidgeted, paced, and pouted. He was quiet through it all, though, mouth set in a grim line, unwilling to open. He didn't beg for a case or cigarettes, and never once said he was bored.

If John had been under the delusion that Sherlock would be receptive to his advice, he'd have suggested he stop ignoring his body and admit that he, too, had fallen victim to the dust and the raspberry-coloured rainwater. As it was, he just watched him, growing more and more agitated himself.

The fourth time Sherlock's mobile rang and was ignored, he put down his book and snapped, "Will you just answer it?"

"It's Mycroft," Sherlock grumbled, breaking his silence. "He has a case for me. A dull one. I have no interest in letting him think I might come around."

John huffed a sigh, glaring at his flatmate. His head was buzzing unpleasantly; he let that excuse his irritation. "Maybe you should. You're going to drive me mad like this."

" _I'll_ drive _you_ mad?" Sherlock sat up from his position on the sofa, scowling. "At least if I were to stare at you for hours on end, I'd have the courtesy to be open about it instead of pretending to read. How long have you been on that page, John? Fifteen minutes? An hour? Do you even know?"

God, he was an arse. It hardly mattered that he was right, that John hadn't read a word for some time; if Sherlock would only be half as agreeable as any normal person, he would have had no reason to stare in the first place. "What, am I interrupting your tantrum? I'd have thought you'd prefer to have witnesses."

Sherlock glared at him another moment, then threw himself back on the couch, descending into silence again. He left one foot on the ground, his heel bouncing up and down rhythmically, and when he caught John staring his lip curled into a sneer.

John left his book, figuring it was a lost cause anyway. "All right. If you'd rather keep up your theatrics in peace, I'll be the bigger man and get out." He stood, waited just a moment for a protest he knew wouldn't come, and went to the stairs up to his room.

The buzzing in his head had become more intense during their argument, and spread down through his chest and legs. He was in his room before he recognised it as a kind of arousal, and it didn't take a moment for him to start stripping, deciding on a good, long wank to clear his head.

He was already hard by the time he sat back on his bed, and he wasted no time in getting his hand on himself. He didn't even need to grasp for fantasies, to tease himself; at the first stroke his hips jerked hard, and it felt almost like being burned, in the best possible way. He closed his eyes, let his mouth fall open, and worked himself rapidly.

Unbidden, a scent memory came to him. _Lestrade_. Fuck, but he had smelled so good recently, and that hadn't been the only time John had caught a whiff of that particularly enticing smell: he passed it now and again in the streets, and, more pressingly, it had started to permeate the entire flat — except in his room, it seemed. It was just as well, though. He'd become somewhat accustomed to it and could usually ignore it, but it was subtle, and every once in a while it would sneak up on him and hit him hard, and he'd have to cross his legs or excuse himself.

He had no need for that in his own space, and he almost wished he could have something with that smell on it in his hand, something he could rub all over himself and inhale. Just thinking about it made his cock leak, and then the thought struck him that he could have Lestrade — Greg — there, smelling like that, and god, but that seemed inexplicably wonderful. If Greg was there with him, he could have the scent, could lick it off his skin and rub against him, and he'd be able to have someone else's hands on him, someone to sink his cock into and wallow in that fantastic aroma.

He gasped, suddenly aware that he'd been holding his breath, imagining keeping the scent in and holding it inside him. He was close already, embarrassingly so — or it might have been embarrassing, if he weren't so lost in his fantasy, if he hadn't been alone.

Dimly, he became aware of something, something besides his own strange fantasy, being off. Unusual. On a particularly long, slow stroke, trying to draw it out and hold off for just another moment, it clicked: there, right near the base of his cock, felt thicker, like he was swelling up. It seemed to be growing, throbbing, but it didn't hurt. On the contrary, it felt good, sensitive, like it was a relief when he slid his fist down and squeezed at it.

Some part of him knew he should worry about it. For the moment, that part was overridden by the part of him that just wanted, desperately, to get off.

Pleasure hit him square in the chest as he imagined sitting on the sofa with Greg, both of them utterly, gloriously naked, basking in the scent of the flat and the way it combined with Greg's own smell. He thought about Greg's hand, no, his mouth, thought about it inching down his cock until his lips pressed against that swollen lump, and came.

It took only moments after his orgasm for John to shift from satiated to stunned. He couldn't remember ever fancying a man like that before, or being so turned on by just thinking about how anything, or anyone, smelled.

And there was the matter of his swollen cock. He hesitated only a moment before opening his eyes, sitting up and looking at it, too concerned to let his fear about what it might be stop him from examining himself in a medical sense.

He was still hard, and showed no signs of softening. The lump at the base of his cock was an angry red, and bigger still than it had been before, firm and solid. It pulsed with blood, and when he palmed it he hissed reflexively, overly sensitive and almost pained by the contact.

It didn't hurt, though, not really. There was no soreness to it, and he distantly remembered something about Type II men reporting similar lumps, though he hadn't imagined it would be so large.

He swallowed, carefully moving his hands away from his cock and leaning back against his pillows. Well, that about proved it, then. He felt suddenly like an arse for every time he'd told a patient who was changing to stay calm, to not worry, that they had no reason to assume the changes were dangerous as of yet.

He pulled up his covers, not caring that it was far too early to sleep, and tried not to feel like a mutant freak.

* * *

There were some benefits to the heightened sense of smell, at least. John was becoming adept at identifying which of his patients were experiencing the dust's changes from smell alone, sometimes as soon as they entered the room, and in more than one case it had helped him ask the right questions to get to the bottom of their problems.

He wasn't sure, though, if his new-found ability to notice the hormonal anger of Type I women and Type II men was a benefit or a drawback. On one hand, he could anticipate it when they were likely to get confrontational; on the other, it seemed, at times, like he couldn't help but respond in kind, the smell of their ire feeding his own, making his body thrum with tension. In a few cases, his manner had suffered, and he was nearly ready to tell Dr. Cobb that he needed to be dismissed, that he was one of them, if he could only form the words.

He didn't have the chance.

Jeremy Hanes smelled like a Type I. He described the same pains and fevers most other Type I men seemed to suffer from, and alluded vaguely to changes in certain urges, in the way his body felt. John had no doubt about his patient's condition.

Jeremy’s father, however, was a Type II. John supposed he was probably prone to aggression even before the dust had fallen, from the look of him: his shoulders set as though he were headed to battle at any moment, his nose showing the asymmetry of an improperly set break. He hovered over his son, eyeing John warily as he recommended something for the pain, and held up a hand, shaking his head, when he began detailing what was known about Type I biology.

"Hold on," Mr. Hanes said, moving around his son and leaning into John's personal space. He gave off a wave of that unpleasant anger smell, and John felt his body, right down to his blood, respond. "My son is no half-sex mutant. No one in our family even set foot outside until the streets were all clear, and even if he had, there's no way he'd turn into one of those freaks."

"Dad, stop," the younger Hanes pleaded, red with embarrassment. He remained seated, though, drawing in on himself defensively.

"Shut up," his father barked, his voice growing louder; John imagined that soon someone would come in to check on them, with all the noise he was making. He leaned closer, poking John hard in the chest. "My _son_ doesn't have a cunt, got it?"

John crossed his arms, willing himself to be calm, to not rise to the bait. "You can deny it all you like, but it won't help him deal with it any better. We may not know much about what's happening to him yet, but the signs are fairly clear, and anyone experiencing that much change that quickly needs to be aware of it. With everything we don't know, what could go wrong—"

Mr. Hanes shoved at him roughly, cutting him off, but John was braced for it, wavering but staying upright. "I don't think you get it," he snarled. "My son isn't some queer freak any more than you're a competent doctor."

Oddly, the _queer freak_ comment riled John more than the slight to his medical knowledge. "I've seen plenty of tough, respectable men come through here with the same symptoms, and each of them was a Type I. As a matter of fact, I'd say most of them were a good bit more man than you, Mr. Hanes."

He fully expected the fist to the jaw that followed, but he couldn't stop from reeling back, pain shooting through his face like ice through his veins. He recovered quickly, though, and in a moment had Mr. Hanes flat against the wall, one arm pinning him there, the other going to his throat. Behind him, he could hear Jeremy yelling for help, yelling at them to stop, but it was distant, his anger washing over him in loud, crushing waves.

It took two doctors and the help of four waiting patients to separate them enough to calm down, and the second he did, John felt shame more intensely than he ever had before.

God, he'd hit a patient. It didn't matter that he'd been hit first; he couldn't argue that he was defending himself, not really, not when he knew how badly he'd wanted to force him to the ground, to hurt him until he was weak, defenceless, submissive. He'd wanted to force him to admit that John was the better man, the _stronger_ man, like it was the most important thing he would ever hear.

He was surprised by how kind Dr. Cobb was, even with her stern expression and the way she wasted no time in dressing him down. "I told you I needed to know if you were exhibiting any symptoms," she said with a stern stare. He met her eyes, nodded in agreement; she was absolutely right. He'd been an idiot. "I'm not stupid. I know this isn't you, but until you can keep it in check, until we can figure out how to deal with all this madness, you can't be around here. These people are coming to us for _help_ , for Christ's sake. We need to be level-headed, and if you're a Type II— well, you just can't be. Not right now."

He didn't say anything. It was true, he knew it was, and all he had to comfort himself was her certainty that there would be a solution. He wasn't sure he believed it, but the idea that someone did was reassuring.

"Go home, John."

* * *

It had been a relief when Molly had texted Sherlock, letting him know that Bart's had a handful of bodies displaying Type I and Type II changes. They had been partially taken apart and put together again already, but it still seemed like the best way to get a first-person look at the new and changed organs the dust had gifted them with. And Sherlock had been so unbearably agitated, so bored, while the strange smell in the flat had only become stronger. John felt certain that if he remained there without work and without more than shopping to take him away for another minute longer, he'd either strangle his flatmate or wind up with a serious friction burn on his cock.

He hadn't figured it would be worse in the morgue.

Yes, Sherlock was distracted, and quite gleeful in his examination of the corpses, pulling at pinkish tentacles and poking around inside them at newly-grown organs. Unfortunately, the smell of the flat had been carried with him, and it made John's head swim and his cock twitch in his pants. He realised he would have to come to terms with the fact that the smell was coming from Sherlock himself, that it was just how Type I men smelled.

And then there was Molly. He'd found her smell hard to bear before, but it had only become worse since he'd last seen her. There was no doubt in his mind that she was a Type I herself, but with her, it resembled the smell of Mr. Hanes and other Type II men. It wasn't something he would have called unpleasant before, but something about the musky, spiced scent drove him mad. 

She wouldn't stop staring at Sherlock.

That was par for the course; John had never seen her around Sherlock without her eyes on him, following him around and hoping for the tiniest scrap of affection. He'd felt for her before, even felt a bit of camaraderie in that void left by Sherlock's callous dismissal of others, and at the worst of times pitied her for her misplaced longing. He'd tried to gently encourage her away from it, once, but it had seemed hopeless and, in the end, mostly harmless.

Suddenly, it seemed quite the opposite. The way she squirmed while watching him take a magnifying glass to a Type II's genitals grated on John's nerves; the way she sighed and flushed seemed an affront to all decency. It seemed ridiculous that she would still be so invested when Sherlock had made his disinterest clear, and the wild look in her eyes stirred a protective impulse in him.

He cleared his throat, frowning when it failed to capture her attention. "Molly?" he ventured, unable to keep the irritation out of his voice.

"Hm?" And still she didn't look at him, biting at her lip.

"Can I have a word?" He waited; with no response forthcoming, he raised his voice: "We need to talk."

There, that was loud enough to even distract Sherlock, though he earned a scowl for his efforts. Molly looked startled and more than a little irritated, but she gave him a curt nod. "All right. What about?"

"Alone — somewhere else, if we can?"

With a tight smile, Molly led him away, into a smaller room off the side of the morgue. It contained a number of neatly organised, sterile instruments, and a thankfully empty autopsy table, which she leaned against, folding her arms over her chest and looking more confident and defiant than he could ever remembering seeing her before.

It didn't deter him, though it did make him realise he was likely in for more blustering than he'd have liked.

"Well? What is it?" she snapped, sounding every bit as irritable as John felt.

"Look," he began, then stopped, licked his lips. She traced the movement with her eyes. "Don't you think this has gone on long enough?"

Molly's eyes narrowed. "What, exactly, is 'this'?"

John gestured vaguely towards the room behind him with one hand. "This whole pining for Sherlock bit you have. You do realise it's ridiculous, don't you?"

Her mouth opened in a wide, mean smile. "Oh my god. You've got to be kidding me! _You're_ telling _me_ my behaviour around Sherlock is too much? _You_? I only get him coffee, for god's sake; I don't wait on him hand and foot! I don't get things for him from his own pockets! If I'm pining, you're obsessed!"

John squared his shoulders and clenched his fists. He knew the arguments he should make: that he did it all reluctantly, that he had to make compromises for the sake of living with Sherlock, that he wasn't obsessed at all. Instead, he said, "He hasn't rejected _me_."

Some part of him recognised that they were acting a bit like children. He only hoped the room held sound well, and that Sherlock was distracted.

The larger part of his mind was preoccupied with recognising that Molly was gearing up to punch him. He wavered a bit between his anger begging for him to respond in kind and his sense and nature scrabbling for a better way out.

He didn't have time to make a decision, but, as it turned out, he didn't need to. The hard knock to the jaw he expected never came; instead, he was yanked forward until his mouth fell against hers, teeth bumping painfully. Molly kissed him hard and desperately, her hands grasping unrelentingly at his collar.

John willed his hands to push her away, but he could only succumb to the same insanity that had taken her, pulling her closer with his hands at her waist. He had no specific attraction to her, though she was an attractive enough woman, but the feel of her touch, of any touch at all, set his skin alight with satisfaction. He felt as though he needed skin-to-skin contact as badly as he needed air in that moment, and if he was enough to scratch that itch for Molly, she was for him, too.

She pulled away, turning them and backing him up to the table. "I can't stop thinking about him," she moaned. "I feel like I've been horny for weeks. Is— is that what it feels like for you?"

John just nodded, struggling to get up onto the table without breaking contact with her body. Molly crawled up after him, taking off her coat and throwing it to the side.

"Good," she said. "That's good."

She began hiking up her skirt. John was distracted momentarily by the feel of her smooth thighs under his hands, running his fingers across her skin and making her shiver.

"Your clothes," she urged, pushing his hands away. "Come on."

"Right." Suddenly his zip and buttons seemed that much more offensive, and at the same time harder to deal with, but he managed to get them undone. He pushed his jeans down his thighs as best he could manage with her kneeling over him. The moment his cock was bared, hard and red, Molly's hand was on it, more sure and steady than he might have expected.

"You're big," she murmured approvingly. She played with his foreskin, pulling it up as far as she could before easing it back down. With her other hand, she teased herself through her knickers. "Do you have a condom?"

"Shit. Ah, yeah, just let me..." He felt through his pockets, hoping he still had one on him. A moment later he made a noise of triumph, pulling one out and quickly tearing the packaging open. He despaired at the loss of her hand on him as he rolled it on, fighting to keep his fingers steady.

The second it was on him, so was Molly, pulling her knickers aside to sink down on him with a grateful moan. John echoed it, falling back onto the cold metal of the table and snapping his hips up into her warmth, ineffectively; her thighs kept him pinned, subject to her whims. She wiggled a bit on top of him, getting a feel for him, before rising up and dropping back down.

John gripped the edges of the table. He had no desire to regain control of the situation. The sensation was like a gulp of water to a dry mouth: not quite enough, but far, far better than nothing. She still smelled wrong, but he ignored that, relishing the heat of her tight, wet cunt.

Abruptly, though, she slowed her movements, moving only incrementally on his cock. "Hold on," she breathed. "This isn't working."

John was about to protest — it was working for _him_ , damn it — but a new sensation stole his breath. It seemed like the inside of her was undulating against his cock, and he realised she was making use of her Type I changes. Slowly, a dozen slick tentacles, each about the width of his middle finger, emerged from her cunt. A few of them wrapped around his cock, their tips stroking at his balls, while the rest slipped further back. He thought about protesting as they probed at his arse, but there was little that was unpleasant about the situation. It wasn't as though he'd never had a finger inside him before, after all, and his cock was not lacking in attention itself.

Perhaps it should have seemed weird, but he reckoned he had no right to cast stones; the bulge at the base of his cock was already expanding, and the tentacles around his cock stroked at the sensitive flesh rhythmically, leaving wet trails behind. They felt like wet, smooth fingers, or like strong, slim tongues. They licked at him, gripped and stroked, and _pushed_.

A bundle of tentacles, wrapping around each other to increase their girth, pressed into his arsehole. Simultaneously, Molly sank back down on him with a throaty moan, throwing her head back. The swelling in his cock was to the point that she could no longer slide down to the base of him, but with the tentacles taking up the slack, he had no complaints.

"Touch me," Molly urged, grabbing his hands and pulling them toward her body. John struggled up, half-sitting, and obeyed. His left hand went to her clit in a familiar gesture, rubbing at her just firmly enough to make her squirm on him. He felt the tentacles inside him respond, pulsing and thrusting.

With his right hand he pushed up her top, mouthing at what skin he could reach. She spared one hand to help him, releasing the clasp on her bra so that he could more easily push it aside, sucking one pert nipple into his mouth.

"Oh _god_." Molly began to pant, her hands in John's hair, holding his mouth to her breast. She let out a whine as he bit down lightly before switching to its twin, his hand taking up the slack.

John's hips jerked hard as the bundle of tentacles inside him brushed his prostate. Noting his reaction, Molly reached for it again. She gasped as he thrust up into her, meeting her hard as she descended on him. The pressure inside him increased, and he groaned as he realised her tentacles were getting thicker — or a part of them was, at least. When they'd slipped in one at a time, he had hardly noticed their girth, but suddenly it felt like too much. It wasn't just pain, but an overwhelming of sensation, prompting a spark of panic he was too lost in sensation to do much about.

Luckily for him, Molly seemed just as surprised by it, and with a quiet _oh_ she slipped them out of him. In the next moment her body tensed, her eyes closed, and in a strangled voice she cried out, " _Sherlock_."

It didn't even cross John's mind to be offended. Instead, it served as a reminder. He thought of the scent that followed Sherlock, the smell that had pulsed through his senses and amped up his arousal, and the tension that had lead to his anger, to winding up on an autopsy table balls-deep in a tentacled pathologist, and it suddenly made sense. It _was_ all about Sherlock, about his smell, not unlike Lestrade's or that of any number of his patients, but so much more intense. If he closed his eyes, he could almost imagine it was Sherlock he was with.

He turned his face from Molly's breast, bit his lip, and came with bursts of colour on the backs of his eyelids.

Neither of them spoke for several minutes. Even after they separated, both remained silent, rearranging their clothes and cleaning up as quickly and carefully as they could. While Molly set to making sure the table was sanitary, John was busy replaying everything that had happened since they'd entered the room. He couldn't quite figure out exactly how they'd arrived at the point that _sex on an autopsy table_ had seemed like the logical conclusion to their argument.

"We probably shouldn't do that again," Molly said finally, her eyes fixed on her hands.

"Didn't think I was that bad."

Her head snapped up, eyes wide. "Oh, no! I didn't mean that at all; it was— well, it was—"

"I was joking." He gave her a small smile, and she relaxed fractionally. "You're right, actually. That was... satisfying, but probably better not repeated."

Molly nodded, looking more relieved as he spoke. "Thank god. I was worried it was only me. It didn't feel right, did it?"

"No," John agreed. "It helped a bit, though."

"Sort of like scratching a bug bite, wasn't it? I can already feel it starting to itch again."

John felt it, too. Although the need to do something about the way his skin seemed to hum had abated, it still had a distant pull on him, coming slowly closer like the tides.

It took him a moment to recognise why his head was so clear, the need so far away: the smell. The room they were in, sealed off as it was, smelled unpleasantly like the two of them, with an extra sterility to it after Molly's fretting, with none of the sweet, pulling scent he'd grown used to living in over the past few weeks.

Suddenly, Molly straightened up, clapping her hand over her mouth.

"Oh, no. I said his name, didn't I? Was I loud? Do you think he heard?"

John grimaced a little as soon as he thought about it. It seemed very likely that Sherlock had. Though he had faith in St. Bart's walls, he wasn't sure they were built for keeping a detective's sharp senses from hearing that sort of thing.

"You go," Molly said, waving him away. "I'm just going to stay in here and never come out again."

John thought about arguing, but he couldn't think of anything to say to comfort her. Instead, he took a deep breath, opened the door, and dove back into the thick, intoxicating smell of _Sherlock_.

The man in question appeared miraculously undisturbed, still wrist-deep in a Type I man's abdomen. Of course, John knew all too well that undisturbed did not mean unaware when it came to Sherlock. He crossed the room to join him, peering into the open body.

"Those new?" he asked quietly. He didn't want to be intrusive, but he was curious, and the man before him was definitely sporting what appeared to be a set of organs that was decidedly not standard for a human male.

"Yes." Sherlock pointed to one, wedged in front of a kidney. "The colour of it almost resembles scar tissue, and yet there's no damage to any of the adjacent tissues. I can't discern its function just yet, but it doesn't seem to be any sort of ordinary shape, like it grew around what was already there."

John looked at Sherlock's face, somehow serene in his concentration. "Must've hurt, then."

Sherlock tensed.

"Look, if this is what's happening to you, you have to make sure—"

"If you're going to insist on being useless," Sherlock snapped, interrupting him, "I'd appreciate it if you could do it a bit more quietly next time."

John was sure he should have felt at least a little embarrassed, but as he stepped back, letting Sherlock examine the body in silence, he only felt content and, bizarrely, like he was waiting for the world to fall into its proper alignment, as it most certainly would.

* * *

John often wished that Sherlock would be more honest with him about his health, but then, he wished for an awful lot of hopeless things when it came to Sherlock.

Since the morgue incident, he had given up on trying to pretend he wasn't watching his flatmate like a bird of prey. If the mood struck him to take his turn in observing, he would put the paper or his laptop aside, lean back in his chair, and just look.

Sherlock, similarly, had given up on calling him out on it, though he maintained the pretence that he was ignoring John. In fact, he made a point of appearing to ignore John in most situations, unless he needed him directly. At times it was as though he believed plates floated to him on the air, laden with food and drink, or that his phone, still constantly buzzing with calls and messages from Mycroft, deposited itself next to his ear on its own.

But he was tense. Constantly. Consistently. It worried John, as he could no longer tell if it was his own presence — and, he suspected, his smell, as well as his sometimes abnormal reactions to Sherlock's — or a persisting pain. Although he knew Type I men were experiencing rapid tissue growth, he couldn't be sure of how long it would take in any given individual, or even if it would ever stop. For all he knew, for all anyone seemed to know, it might have been a sort of cancer, growing and mutating until it crushed a person from the inside out.

Or, he supposed, it might have been nothing more than another fit of boredom. It was not unheard of for Sherlock to ignore John, after all, though that happened most often during cases, nor was it uncommon for him to become practically catatonic when the absence of work weighed particularly heavily on him. The stiff way he sat around was certainly new, as Sherlock was particularly good at imitating one of Dali's melting clocks even when he was under the worst sort of stress, but it wasn't out of the realm of the possible for it to be just another symptom of his self-pitying sulks. It had been a while since his last case, after all.

John was still a doctor, though, and couldn't help but worry.

As a result, a deep sense of relief washed over him when he saw the tension sluice off Sherlock like water. He was standing at the window, his back to John, and although he had been looking for ages, in that moment he was watching, intent.

"Lestrade's here," Sherlock announced, as though the room was full of people who desperately needed to know. "He has a case for me."

 _Good_ , John thought, watching Sherlock drop down onto the sofa, his dressing gown spilling down around him and making the move look much more graceful than it had any right to be.

In the silence, they listened together for the knock on the door. John could only barely make it out, but he was sure that to Sherlock, it was as sharp and clear as anything. Mrs. Hudson would surely answer and send him up; by the time Lestrade got to their door, Sherlock would certainly look as though he hadn't been waiting for him at all.

They waited. Mrs. Hudson's voice was even fainter than the knock, her words impossible to make out.

Eighty seconds had passed when Sherlock raised his head. "He should be coming up the stairs by now. What's keeping him?"

John shrugged, aware that Sherlock didn't need a response from him at all.

Sherlock sat up, listening intently. "Mrs. Hudson shouldn't be distracting him this much."

"Maybe it's not that urgent," John offered, hoping it was.

"No, he was walking with intent. He was _focused_." Sherlock stood, marched to their door, and threw it open.

Half a second later, he slammed it shut, turned, and stormed off to his room, looking as though the world had done him the most grievous of wrongs.

John sat there a moment, expecting Sherlock to come out again, perhaps dressed in proper clothing, or bearing something he'd nicked off Lestrade as a peace offering. He didn't. With curiosity prickling at the back of his neck, John crossed to the door and opened it, cautiously.

The smell coming up the stairs nearly made his knees give out.

He recognised half of it as the same smell that had come from Lestrade before, only a dozen times more potent. It made his mouth water and his cock harden almost painfully quickly, made it impossible to not breathe deeply.

The other half was something he'd only caught faint whiffs of, in passing. It smelled a bit like Molly, but different somehow, and after a moment he realised it had been coming from Mrs. Hudson's flat all along.

The implications hit him just as something hit the wall below, and he heard a deep groan that could only be from Lestrade. He quickly shut the door and followed Sherlock's example, retreating to his room — though, he supposed, it was likely for a very different set of reasons.

Sherlock told him later that there had been a case, and an important and interesting one, too; unfortunately, Lestrade had suddenly claimed an illness to the Yard, and wasn't seen for three days. The DI who had taken over the case in his stead refused to work with Sherlock.

Boredom and tension returned.

* * *

Laundry was typically off-limits, by implication rather than order. John washed his own clothes, and suspected Sherlock paid someone to wash his, even the items that didn't need any special treatment. There was no reason for either of them to touch each other's clothes, unless, of course, Sherlock had suddenly decided that he needed to study the burn rate of polyester or how wool reacted to various types of acid.

John had never touched Sherlock's laundry. It was partly from respect, and partly because he worried that if he ever did, washing it would instantly leap from favour to expected chore.

It felt a little bit thrilling, then, to be picking through Sherlock's lightly soiled clothes, looking for just the right item. John couldn't say what had possessed him to sneak into his flatmate's room, except that he'd seen an opportunity when Sherlock had skulked off to shower for the third time that day. 

John wondered if that was worth worrying about. He couldn't say he didn't appreciate it, though; it kept the smell of the flat from becoming completely unbearable, at least.

He was already hard as he picked up and set aside Sherlock's things delicately, using only his thumb and forefinger. He wasn't worried about discovery; he was certain that even if he tried to hide the fact that he'd been there, Sherlock would know instantly. On the other hand, he was worried that if he wasn't careful with himself, he might never make it out of the room.

There had been a girl, when he'd gone out to do the shopping. A woman, rather. She had been tall and auburn-haired, lovely and smartly dressed, exactly the sort of woman he'd have tried to chat up before— well, before he developed a lump in his cock and a disturbingly intense reaction to the way his best friend smelled. So he'd tried, and he'd been truly hopeful, but she'd turned him down because, of course, he didn't smell right to her.

She'd been apologetic about it, at least, and careful to say exactly what she meant. John was sure she might have been more receptive herself before the dust, but neither of them could turn back time.

He was also sure that if he hadn't had that disappointment, if he hadn't been so resigned to accepting what he'd become, he might have been able to stop himself from deciding to steal Sherlock's dirty clothes.

He still couldn't turn back time.

He was trying, really, to think rationally though the haze settling in over his mind. He couldn't take anything that needed dry cleaning, or anything he couldn't afford to replace. That left pyjamas, mostly, one of the cotton items Sherlock liked to laze about in when he was particularly bored. Pants were too intimate, too much of a violation. Bottoms were fine, but didn't retain quite enough of that smell. A shirt, though — a shirt was impersonal enough, and yet with its sleeves and folds, tucked right up against sweating skin, it would undoubtedly smell fantastically of Sherlock.

There. He picked up a blue one, let it hang down from his fingers. A bit old and worn, in good condition but nondescript. It wouldn't be missed much.

His decision was nearly made, but he had to check, had to be sure. He crumpled the fabric in his fist, bringing it close to his face, and inhaled.

It was _glorious_.

It took him a second to realise he'd frozen there, standing in front of a hamper full of disturbed laundry with his hands in a shirt that wasn't his own, smelling it like the sort of person he'd always thought of as perverts. With some effort, he lowered the shirt, took a shuddering breath, and left the room.

Upstairs, in the safety of his own room, he threw the shirt on his bed, not daring to touch it again until he had his own clothes off. His hand was already on his cock when he picked it back up, letting out a long, deep groan the moment it was under his nose. He lay back, stroking himself slowly. He wanted to draw it out. There was every possibility that Sherlock would soon finish bathing and would figure out exactly what he was up to in a matter of minutes, but John couldn't bring himself to care. Fantasising about the smell had been stimulating enough, but actually having it there, saturating the shirt's collar and underarms, was incredible.

The base of his cock was already beginning to swell, despite the lightness of his touch. He let himself thrust into his hand, keeping the circle of his fingers loose and flexible. He rubbed the soft fabric over his face with his other hand, inhaling deeply, his breathing shaky. It smelled of sweat, chemicals, smoke — he wondered when Sherlock had managed to get his hands on cigarettes — and, above all else, that indefinable odour that permeated the flat.

He had smelled it on the streets and in some of his patients. It was always arousing, at least a little, and always made his head swim, but it was just slightly different each time, and whatever it was that was unique about Sherlock's own particular scent, it drove John mad. He thought that if he could distil it, he would bathe in it, drink it down, make it a vapour and inhale it. He was sure he could never have enough of it.

He closed his eyes, letting his mind wander where it would. With the smell of Sherlock cradling him, it was impossible to picture anyone else. Though in reality he'd been in a terribly foul mood for what seemed like ages, John pictured him pliable and enthusiastic, wanting to touch and, even more, to be touched. He imagined how he might be interested in studying the reactions of a living Type II male's body, how it would only increase his interest in John, specifically, how he would touch and taste to get the complete experience of it. He imagined Sherlock getting lost in the carnality of it, rubbing himself against John's body as though he was helpless to do otherwise. 

Unconsciously, his hand sped up, his fist tightening around his leaking cock. The sharp scent of the shirt brought forth the memory of the way a patient, young Mr. Daniels, had insisted that there was something changed about him, and the way his body had gripped and pulled John’s finger in.

Oh _god_. John hadn't yet allowed himself to think about it, but there it was: he was absolutely certain Sherlock's body had changed in the same way Mr. Daniels' had, like that of every Type I male, and the thought of pressing his fingers into Sherlock in that way, of Sherlock's body _begging_ to be penetrated, had him biting down on the shirt, his tongue pressing the fabric to the roof of his mouth. He pulled his hand away from the cloth, using it instead to squeeze at the sensitive, engorged bulb at the base of his cock and imagine it taking the place of his fingers inside Sherlock, and how Sherlock would moan as he pressed his expanded girth _in_.

The cloth stuffed into John's mouth muffled the strangled noise he made as he came; it seemed to go on for longer than it ever had before, pulse after pulse, so much that he wondered if he hadn't broken himself by masturbating too often. When it finally stopped, his cock was still hard, the base of the shaft still round, and he was slick with sweat and too tired to move. Though he was reluctant to do so, he made himself let go of the shirt, tossing it over the side of his bed.

The shirt eventually made it through the wash and back into Sherlock's belongings, but not before John learned what it felt like to have it wrapped around his cock and soaked with his own come.

* * *

It was the WHO that finally declared itself the authority on the maroon dust from nowhere and its inexplicable effects on humanity. When they released an official report, it was a constant topic for more than thirty-six hours, saturating papers and news broadcasts all across London — and, John supposed, much of the world.

They rejected the categorisation of the biological changes by the degree of change, insisting instead that the utility of the organs and the behavioural changes were more important, both in understanding the changes themselves and in what they meant for individual treatment, though they were vague enough on what that treatment might be that John was certain there was no viable cure on the horizon.

Their choice of terminology didn't sit well with many: of the changed population, which the WHO estimated was nearly half of all people worldwide, the Type I men and Type II women, now called _omegas_ , resented the implication of inferiority the word brought with it; some Type I women, paired with Type II men as _alphas_ , decried the masculinity of the word. Of the remaining people, tentatively referred to as _betas_ , many insisted that there should be no term applied to them at all, as they were unchanged. There were outliers, and those who preferred any warmer terminology than what had been used, but for days it seemed to be all anyone could focus on, the streets of London singing with an energy refocused on the easy argument of words over the difficult and unanswerable questions they had been facing.

Still, the words seemed to stick, and John thought he could _see_ people conform to their new identities like stiff new clothes. He wasn't sure the sight was a pleasant one, but it seemed to give many peace of mind.

 _Alpha_ , he found himself thinking, looking at himself in the mirror. A secondary sex, some called it, and he could only worry about how that would muddle biological terminology, because it was easier than acknowledging that his idea of himself as nothing but male was crashing down around him. _Alpha_ , he thought again, and straightened his back, trying to find pride hidden in the word.

Alpha male, alpha wolf. Did he want that domineering, aggressive image for himself? He thought of his recent behaviour, of the way he'd hit Mr. Hanes, the snarling thoughts that had come to him unbidden when he'd seen the way Molly looked at Sherlock. Perhaps they held a certain truth, but he didn't have to accept it. He could fight it, be his own man. Sherlock was.

Sherlock, yes. Omega, but he couldn't imagine applying any sort of submissive lower-tier identification to that kind of genius. If Sherlock was an omega at all, it was nothing but a Greek letter, a footnote to everything else he was.

If it could be that way for Sherlock, John decided, it could be that way for him, too.

Even a footnote required some attention, though, and it was with that certainty in mind, that idea that it could be insignificant to their identities and yet still worth talking about, that John sat in his armchair in the sitting room, cleared his throat, and very determinedly did not breathe deeply.

Sherlock, stiffly reclined on the sofa and on his second day of voluntary muteness, only turned his eyes towards John to acknowledge him. It was the most John might have hoped for, anyway.

"You're going to have to deal with this eventually, you know." Not his best opener, but mincing words with Sherlock Holmes never did much good. "Your body's changed significantly. I know it's all meaningless to you, but it does need some basic tending to."

 _You should see a doctor_ , he didn't say, less because he knew it was advice that would be immediately dismissed and more because he'd be tempted to offer his own services. He was sure that wouldn't go well for either of them.

"You've got to think of how to prote— how to restrain yourself. I know you think you're completely in control, but so did every person who wound up in the middle of a sex offence case after this all started. They're reworking the bloody consent laws, even. It's all a mess, and if you— if _we_ aren't all careful, if we aren't aware of just how our bodies have changed, the consequences—"

"I am perfectly aware of myself," Sherlock cut in, his voice slightly dry after his neglect. "I always say and do exactly what I mean to, unlike the rest of the world. Go back to worrying about your compromised sexuality; I, for one, don't care what new organs I may have so long as they don't get in the way of my mind."

It took John considerable effort to unclench his jaw a moment later, puling a tight, insincere smile. "Right. Of course. You might want to think about how you're going to deal with everyone else, then. Most of the world isn't like you. How will you say 'no' if you are physically incapable of saying anything but 'yes'? Or what if someone else wants to stop, but doesn't know how?"

Sherlock huffed and rolled his eyes, his impatience with the topic already beginning to boil over. "Most of the world isn't you, either, John. You might have noticed that a large portion of London can't stand to be around me for more than a few minutes; I hardly think I'll be anyone's top choice now."

John stared at him a moment, then laughed hollowly, shaking his head. "God, you've got no idea, have you?"

Sherlock closed his eyes, already beginning to check out of the conversation. "I'm sure you'll enlighten me."

"You smell," John began, then stopped short, licking his lips. Amazing? Fantastic? So strongly it was a wonder all of London didn't pound at their door just to get a better sniff? "You smell like sex."

Sherlock's eyes opened at that, a mix of panic and something else swimming in them.

"You smell like a wet dream hung out to dry," John continued, aware that he was babbling but unable to stop himself. "Like you've been out in the sun and _ripened_ , like if anyone opened you up you'd taste like— like fucking. The entire flat smells like a bloody brothel, except all the bad parts of it are taken out and what's left over is just the wanting part, constant and suffocating and— and you think you can go out like that and no one will notice?"

He realised as he stopped that he was breathing fast, hardly able to catch his breath, and that he was terribly, obviously hard. He couldn't even feel ashamed, knowing that Sherlock could see the way he tented his jeans. He'd dug his fingers into the arms of his chair, and he wasn't sure he could let go without grabbing his flatmate and doing something completely terrible.

The silence that drifted in the air between them rubbed John's nerves raw. The tension was a pendulum coming ever closer, and he was sure that at any moment it would cut him in two and destroy everything he had.

But Sherlock rose after a minute, not pausing for even a moment. "I'm going to shower, then. I hope you take your own advice while I do; I won't always be able to bathe four times a day when we're on a case."

John waited until he heard the door click shut and the water turn on to relax his death-grip on the chair, his fingers aching. He scrubbed a hand over his face and realised he was sweating. He thought about going out into the cool evening air for a walk, but as he stood, he realised he wouldn't get very far; the bulge at the base of his cock — his _knot_ , the WHO called it — was already huge, and he felt as though one wrong smell outside on Baker Street would do him in.

He went up to his room and imagined every awful thing he was afraid of doing until he came.

* * *

Sherlock was not home, that much was certain. John wasn't actually sure that Sherlock had even been in when he'd left the flat to do the shopping, but there was no mistaking his very conspicuous absence by the time he returned; the smell of him, though still present, was fading, like the lingering aroma of a snuffed out candle. His bedroom door was open, he was not in the sitting room or the shower, and his beloved coat and scarf were missing from their customary spot beside the door.

It was a relief to be able to breathe without inhaling him, John realised, though at the same time he couldn't help but miss the scent. He only barely resisted the urge to bury his face in the cushions of the sofa, marching past it resolutely and deliberately not looking around as he put away his purchases.

He'd tried flirting with a woman at the shop, hoped it would take the edge off, at least. It hadn't; apparently something about John's approach had been a bit too much, and she'd burst into tears and told him that he was nice enough, seemed wonderful, even, but she was _married_ , and they were both omegas, and she'd taken her ring off because she couldn't stand it anymore, and by the end of it he wasn't sure if he felt sorrier for her or for himself. He supposed that was selfish.

He'd felt selfish very often, since the dust had come down.

He tried not to worry about Sherlock, telling himself it was likely he'd simply decided to finally take on whatever case Mycroft had been pushing at him. A little reprieve from his boredom could only do Sherlock good, John thought. 

He made dinner and didn't wonder about whether or not Sherlock smelled as good to other alphas as he did to him — almost.

He was still doing the washing up, dragging out the task under the guise of trying to scrub out permanent stains, when his phone announced with a _ping_ that he had a new text. He nearly dropped his phone as he pulled it from his pocket, holding his breath.

**Assistance needed. Urgent. SH**

As he read, another text came in.

**May be out of my depth. SH**

**A case?** John wrote, unable to dispel the anxiety settling in his chest.

**Yes.**

And then, a moment later:

**No.**

An address followed shortly thereafter as John pulled on his coat and shoes, his heart pounding in his ears. As he raced down the stairs and out into the street, he forced himself to remember every other _urgent_ text Sherlock had ever sent him, from missing combs to possible murderers with knives at his throat. 

He'd never been _out of his depth_ before, though.

The address brought John's taxi to an unfamiliar corner with no sign of Sherlock in any direction. He shoved the fare at the driver and leapt out, turning around fully twice. It was late enough for foot traffic to be light, with a few small crowds gathering outside pubs down one street, but his flatmate was still not in sight.

He checked his phone, worrying — hoping — that he'd got the street names wrong or missed a text updating his location. No luck; he was right where Sherlock had wanted him to be. He shoved it back into his pocket, trying to be annoyed and failing.

A wave of desire nearly knocked him over as a light breeze carried a familiar scent to him. Orienting himself to it, John hurried down a street full of small, uninteresting shops, sniffing the air and very carefully not wondering about what he was about to find.

The scent grew stronger just outside a narrow alley, and despite everything his good sense and his years of experience at Sherlock's side told him about running into anything blind, John turned into it sharply. The light from the street didn't quite reach the recess Sherlock had hidden himself in, but John could smell him so sharply it hardly mattered, except that he almost didn't notice the other person with him.

"I found him first," the stranger growled, fair and broad and hateable in every possible way as he crowded Sherlock up against the wall. "He's _mine_."

The only suitable answer to that, John felt, was a fist to the mouth, followed by a hand on the man's collar to drag him away and reintroduce him to the pavement out by the street. He watched him scramble away, feeling a deep, vicious satisfaction at the way he kept his head down and did not look back. In the next moment John took his place, too close to Sherlock to properly check him for injuries the way he told himself he should.

Sherlock was sweating profusely in the cold air, his hair sticking to his forehead. His mouth was slightly open, his trousers more so, revealing a pale thigh and — John swallowed thickly — Sherlock's hard, reddened cock, its head exposed and shining with pre-come.

John felt himself swaying forward, and he fought the urge to touch. Sherlock hadn't said he wanted him to, he reminded himself, and closed his eyes. "Jesus, what are you _doing_?"

Sherlock merely panted a moment, as though coming off a long, hard run, before answering. "There _was_ a case. Dull, really, but— I need relief. I need—"

"Not what I meant," John said, cutting him off. He wasn't sure he could stand to hear any more. "You claim to be a genius and yet you wander out alone like this? You could have been hurt, or—"

Sherlock cut him off with a groan, his hands darting up from where they were pressed to the wall to pull John closer. He thrust against John's thigh, his eyes wide and desperate.

"God," John breathed, shuffling closer. He put his hands on Sherlock's sides, pulling him closer and relishing the feel of the firm heat of his cock through his jeans. "What if I wasn't here in time? Would you have let him have you?"

"Does it matter?" Sherlock asked, rutting harder against him. "You're here now. John— this isn't enough. I need it. _Please_."

John was sure he knew, but he had to ask anyway. "What? What do you need?"

"Fuck me," Sherlock gasped, no trace of shame in his voice.

With the smell of him filling John's nose, the warmth of him crowded up close against his chest, there was no way John could refuse him. He glanced up at the street; it was dark enough that they wouldn't be seen, but if they were heard, it would be all too easy for someone to discover them. "Can you be quiet?"

"No." At least he was honest.

It didn't make any difference at that point, John realised. Sherlock was asking for it, literally, and he could not bring himself to walk away; as it was, they were pressed together from shoulder to thigh, and it was difficult enough to step back just so Sherlock could turn, pressing his forehead against his arm where it laid against the wall. His other hand grasped back at John blindly, trying to pull him closer even as John moved in on his own.

There was little time for finesse. As soon as he had Sherlock's zip all the way open, he shoved his trousers down as far as he could, tugging his pants down after. They were damp, his thighs as shiny as his cock, and it took John a moment to realise that it was coming from Sherlock — from his arse, leaking out some kind of biological lubricant. He sucked in a shaky breath as he ran his fingers up through it, relishing the slickness of it and pressing two fingers into him.

He was tight, yes, but startlingly pliable. John couldn't get his cock out fast enough, and then— _oh_ , the heat of him. It was an awkward position, the way Sherlock had to bend his knees and press his forearms against the rough brick, but John couldn't imagine anything better, couldn't picture anything outside of that very moment. He pressed his mouth to the back of Sherlock's neck, felt the brush of his soft curls against his nose and cheeks, and drew back to thrust.

"Oh," Sherlock said, pressing back into him. "Fuck. That's it, fill me up. Come on, John, I need it."

"Yeah," John agreed, thrusting with all the force he could muster. It didn't feel like enough, like it could ever possibly be enough, but he reached for it anyway, unable to stop himself. "Yeah, you do. Tell me what you need."

Sherlock moaned, dropping his head down, his forehead laying against his arm. "Your cock. Your _scent_. God, it almost hurts when you pull out."

John agreed wholeheartedly, and shifted his stance, making his thrusts shorter, keeping more of himself inside. "That's right. You need _my_ cock. That bastard you were here with — he couldn't have been enough for you, could he?" It felt insane, almost humiliating to be saying it, but he couldn't stop himself from hating the man he'd chased away, wanting to degrade him in Sherlock's mind and keep him away forever.

Sherlock shook his head against his arm, gasping and panting. "I need to come — I _need_ to, have to come while you're inside me, please, _please_ —"

"Shh." John ran a hand up from Sherlock's hip up his side, soothing even as he thrust harder, quicker. "You feel amazing."

Sherlock made a soft hiccuping noise, and then, as if to cover it, asked, "Have you done this before? With another man?"

"No." That didn't seem to matter. "Have you?"

"Not from this angle."

 _Good_ , John thought viciously. It felt like he was being driven out of his mind as he became aware of two unfamiliar sensations: first, the feeling of his knot swelling _inside_ another person, making it difficult to draw back and sending aching shocks of pleasure to his spine; and second, that small opening inside Sherlock, just beyond his prostate, that seemed to be reaching for him, opening up to the head of his cock and begging him to press inside. He wrapped an arm around Sherlock's waist, pulling him closer and seeking to do just that.

" _John_ ," Sherlock pleaded, almost like a sob. "Is that— That's your knot, isn't it?"

John couldn't answer, grinding his hips against Sherlock's, grunting with the effort of trying to get deeper, closer. All the air in his lungs seemed to leave him when his cockhead slipped _in_ , and in seconds his knot was so big he couldn't pull out, though he couldn't imagine wanting to.

"It's perfect," Sherlock babbled, pressing his head down harder into his arm. "God, your cock is _perfect_. Oh, fuck, touch me, please."

John did, seeking his cock out blindly as he pressed his face into Sherlock's back. With just a few too-dry pulls, Sherlock was coming, ejaculate splattering onto the wall and the ground, involuntarily clenching around John's knot. That was enough to bring John to his own orgasm, spilling inside Sherlock for what felt like an impossibly long time, spurt after spurt filling him up even more.

They stood there for a few long minutes, panting and groaning. John kept his eyes fixed down, rolling his forehead to see where they were joined. He'd expected to see his come leaking out around his cock, but no, his knot was keeping Sherlock quite effectively plugged. His mouth went dry thinking about the way it would spill out of Sherlock when they finally separated, the obscene way it would slip down his thighs to join all the slick lubrication already painted across them.

He was a little surprised, actually, that it seemed like he hadn't softened at all, but he did still feel hazily aroused, like he was at the beginning of something rather than the end of it. He wasn't drowsy at all, like he usually felt after an orgasm, either.

"I don't think that was enough," Sherlock said, low and quiet. "I'm going to need it again. Soon. We should get back to the flat while we still can."

John nodded, sighing as he stood and pulled back — or tried to. He was caught, so firmly wedged inside Sherlock, whose arse seemed decidedly less loose than it had been, to get himself out. He wrapped his forefinger and thumb around the base of his cock and gave it himself a tug, his other hand still on Sherlock's hip, pushing him away.

Nothing gave.

"Oh fuck," John hissed, trying not to let wild, animal panic rise inside him. "It's— it's still too big. I'm stuck."

Shockingly, Sherlock didn't appear to see that as a problem, moaning and grinding back against him. 

John had to get through to him. "We can't stay like this." Even if it seemed vaguely tempting.

"No." Sherlock demonstrated his agreement by continuing to grind back, making choked-off, whining sounds in his throat.

The panic settled its claws into John, his mind suddenly shouting in a dozen irrational voices — _what if we never come unstuck_ singing out most clearly — and he pulled away hard, shoving against Sherlock's lower back with his free hand.

The howl of pain that came with his freedom made his gut clench, his hands immediately returning to Sherlock's flesh, holding him steady and exploring red, abused flesh.

"Jesus. Fuck, are you all right?" Nothing looked out of place and he couldn't see any blood, but he didn't dare try to press too hard or press his fingers inside without explicit permission.

Sherlock groaned unhappily. "Don't do that again. Don't _ever_ do that again."

"No, I won't, I promise I won't," John agreed, relief washing through him. "I'll take a closer look when we get back, all right?"

That was when it hit him: he was sitting in a grungy alley, his still-stiff cock hanging out of his trousers, touching Sherlock's naked, tender flesh. It was humiliating, and the worst part was that he was still so very turned on, still tempted to lean in and just smell Sherlock until they could start again.

He distracted himself from feeling like an awful pervert by helping Sherlock back into his clothes, taking extra care when Sherlock whimpered as the fabric dragged against the skin of his thighs. 

The cab ride back to Baker Street was miserable and exhilarating. John knew, without a doubt — from the periodic flicker of the cabbie's eyes back to them, from the way Sherlock writhed uncomfortably against the seat, from the way his knot went down without his cock ever getting soft — that he would be inside Sherlock again within the hour. He almost didn't want it, was afraid that Sherlock felt the same, but he felt helpless against the scent of him, the knowledge that he was still leaking and desperate and _right there_.

John's hand didn't leave Sherlock's thigh for the duration of the ride.

Sherlock ran in as soon as they came to the flat. John trembled with the need to follow him as he paid, counting out notes and coins carefully and trying, desperately, to control himself. The moment the fare was in the driver's hand, though, he burst out of the vehicle and climbed the stairs as quickly as he could.

For only a moment, he didn't know exactly where Sherlock was; John had expected him to drop to his knees the moment he'd got in, had half-hoped he'd get to fuck him across the floor of their sitting room, and a flare of protective worry flew through him when he found the room empty. Quickly, though, a heavenly scent directed him to Sherlock's bedroom, to Sherlock's naked form. His clothes were spilled out across the floor, dropped with uncharacteristic carelessness, and Sherlock himself was laid out face-down and sideways across his bed, his knees drawn up to give John the most spectacular view.

If John had been at all in his right mind or even remotely capable of self-control, he'd have spent time appreciating the view, would have run his hands up Sherlock's thighs, cupped his arse gently and kissed the knobs of his spine.

Well, that was what he liked to think he'd do, when he couldn't remember not wanting Sherlock. Some part of him remembered, but he shoved that part away in the same moment that he pushed Sherlock's hips into the bed, gripped his arse cheeks, and spread him open.

The skin around his hole still looked rough and red, but he was dripping wet and loose enough that it only took a light tug of his thumb for John to open him up.

" _John_." Sherlock sounded pained all over again, but he pushed back into John's hands insistently.

John knelt on the bed, bent over low and awkwardly. He wasn't sure when he'd brought his face so close to Sherlock's anxious flesh, but with the delicious smell of his skin so close, it seemed only natural to keep moving closer, closer, until his nose was pressed into the crease where Sherlock's arse met his right leg.

It was dizzying, being so very close to that smell. He inhaled deeply and, almost unconsciously, let his tongue drag across slick skin.

It tasted even better than it smelled.

Despite the obvious texture and shine of the slippery lubrication running down Sherlock's legs, John had still subconsciously expected to taste sweat. Instead, he tasted _sex_ , the desire and the thrill of it exploding across his taste buds. He licked again, lapping up as much of it as he could and moving in until his tongue swept over Sherlock's balls and pressed in on his perineum, where the taste seemed especially sweet and sharp.

Sherlock _whimpered_ , and John wasn't sure if it was because he pressed back again or if it was his own doing, but suddenly he was licking at Sherlock's arsehole, something he'd never done in his life before, and it made his cock throb. It was only the realisation that he didn't have enough skin-to-skin contact, that he was still bafflingly _dressed_ , that tore him away, standing up just until he could get every last stitch off himself.

Entering Sherlock a second time was even better than the first; there was no hesitation, no question about whether or not he _could_ or what it would be like. He knew he could, and even as he wondered at it he knew it would be incredible, quite possibly the best thing he'd ever felt.

Judging by the sounds Sherlock made, the feeling was absolutely mutual.

It was surprising, then, to find that Sherlock was only half hard. "It's too soon," Sherlock ground out before he could ask. "I can't— I _can't_."

John wasn't even sure how _he_ could, so he didn't question it, just let his body press Sherlock's down, his hands gripping the bedclothes, and pounded into him with everything he had.

It didn't seem to make much difference anyway. When the head of John's cock slipped again into that little space inside him, Sherlock made a sound like he was choking and shuddered all over in unmistakable pleasure. "I'm coming," he said, wondering and lost. "How are you doing this to me?"

John answered with a grunt and a harsh push of his hips. He draped himself over Sherlock's back, pressing him down as he filled him with come, filled him with his growing knot.

In another half hour, they would start again without ever separating, the lingering swell of John's knot sending shivery jolts of pleasure through every nerve of Sherlock's body, but for that moment, they rested, still but for their panting breaths, skin sticking to skin.

* * *

It might have been the morning light that woke John, or nothing more than his body deciding it had had enough sleep. It might also have been the rocking of the unfamiliar bed he found himself in, rhythmic and quick.

He opened his eyes to the sight of Sherlock grinding himself down onto his own fingers, head thrown back, hair plastered to his sweating forehead. Sherlock seemed to know he was awake without even opening his eyes, reaching for him with the hand that wasn't four fingers deep in his own arse.

John was on him in a second, pulling him out by the wrist and replacing inadequate fingers with his ready cock. He hooked his right arm under Sherlock's knee, bending in as close as he could, until he could feel Sherlock's breath on his face.

"Is this going to stop?" he asked desperately. He'd meant to ask _when_ , but that almost seemed too hopeful against the omnipresence of their arousal.

Sherlock didn't answer, didn't look him in the eye. He just rolled his hips up to meet John's thrusts and sucked in air.

* * *

It took three days for it to end, much more suddenly than it had begun.

In the space of two hours, everything grew less desperate. John started to become aware of his gnawing hunger and his aching muscles; they had rested, bathed, and eaten only in the short snatches of time they could bear to be apart, and only because they knew that they would need to eventually, that they'd otherwise keep going until they'd fucked themselves to death.

At the tail end of it, John found himself balls-deep in Sherlock again and wondering how he'd got there. He remembered, of course, but suddenly none of it made any sense. Yes, Sherlock smelled good and felt better, but he was _Sherlock_ , and he was hardly irresistible.

Except he had been, for three days. It didn't seem possible, but it had happened.

He pulled away from Sherlock without finishing, terrified at the idea of letting his knot hold them together again. Sherlock didn't complain, didn't say anything at all, keeping his face pressed into his sweat-drenched pillow.

It was late on a Thursday, and John felt like he'd shed another man's skin, except that underneath he felt filthy and confused.

Sherlock didn't come out of his room for another hour. They didn't speak, hardly looked at each other. They passed one another like ghosts. Through every second of the day, John was acutely aware of every movement Sherlock made.

The next day they silently but mutually agreed to acknowledge one another again, and it was worse. John tried to keep away, and yet whenever he left the flat or huddled up in his room, he itched to return to the sitting room, to find Sherlock. Sherlock seemed similarly drawn to him, and yet he would make vicious, snarling comments, criticisms of John's intellect or clothes, his every habit and decision. John bristled in return, but kept as quiet as he could, until he couldn't bear it any longer and would snap back, then retreat again.

It happened over and over, and still he felt himself being pulled back into Sherlock's orbit.

He asked about Mycroft's case, hoping he could distract the both of them, or at least Sherlock, even for just a little while. "It wasn't important," was all Sherlock would say, or, "He can solve it himself."

It took him long enough to realise that Sherlock was actually afraid to go out again that he felt impossibly stupid even without being told he was. And so he put up with the jabs and insults, held through them as long as he could, and decided that it was better, at least, than every aching moment of silence between them.

On the fifth day, he packed a bag, scratched out a quick note, and checked himself into a hotel.

* * *

The air tasted like guilt.

John rolled over, pressing his face into the cool hotel pillow. Though he had lain there for nearly two hours, he felt no closer to sleep than when he'd first closed his eyes.

He had spent the long, hollow hours since he'd left the flat pacing, trying — and failing — to read the book he'd packed, and staring with unfocused eyes at the television. All the while he'd been arguing with himself, wondering if he'd been stupid to run away from Sherlock, or if they were both better off making the separation permanent.

The latter idea made him feel like there was a weight in his stomach.

He'd given them space, at least. Maybe leaving without facing Sherlock first was the childish way to do it, but he was sure that if it was a cowardly act, refusing to return would be even worse. Besides, he needed to learn to control himself; if it wasn't Sherlock, surely it would be another omega somewhere, until he could get a hold of himself.

It was hard to tell which idea was worse: not being able to resist anyone who had the right smell, or specifically failing where Sherlock was concerned. Both thoughts seemed fairly nauseating, and were made no better by knowing that his new biology, shared by so many others across the world, was at fault.

Yes, guilt; guilt and bile, laced with self-pity. That was the way the air in his room tasted, and if he closed his eyes too hard he was sure he could seek flecks of maroon dust still stuck behind the lids.

He was almost grateful for the panicked yell for help just outside his door at just past midnight.

He was on his feet in a moment, only a little muzzy from his attempt at sleep. He grabbed his room key as he moved, sprinting out into the hall before his eyes even had time to adjust to the light, and hit a wall of scent so thick he physically recoiled.

He nearly turned back, terrified of what he might do if he moved closer to its source — of what he might do _again_ — but he steeled himself and pressed on, unwilling to let his own weakness let someone else get hurt.

Again.

She was only a few doors away, and if John hadn't been able to tell she was an omega in heat from the smell alone, the hand she had shoved up under her skirt would have been a dead give-away. She looked like she was dazed and in pain, and the moment she inhaled and smelled John, she whipped her head around, eyes half-lidded, and whimpered. "Oh, thank god, thank god," she murmured, her whole body shaking.

It wasn't the urgent situation John had been anticipating. At the very least, he'd figured there would be alphas trying to get at her, or someone after her with a weapon, but there was nothing but her and the potent odour of her heat. John's cock, uncomfortably hard already, throbbed in his pants when he realised what she wanted.

Every piece of him wanted to give it to her. His body, his basic biology, had reorganised itself to respond to bodies like hers, to override rational thought and succumb to animal instincts, as though he wasn't already eager enough for something to sink his cock into. She was pretty besides, with short brown hair and wide, expressive green eyes, a small nose and plush lips. And he knew already how good it would feel, if the _incident_ with Sherlock was any indicator, particularly given that he had never been attracted to men before.

It was thinking of Sherlock that snapped him out of it, though, with his hand already running up her slick thigh and his mouth only centimetres from hers. She was arching off the door that was supporting her, trying to press her hips to his, and all he could see was _Sherlock_ , who had looked just the same, with those wild, lost eyes. Sherlock, who couldn't even look at him after.

And all the men and women who'd reported rapes they'd committed, or begged for.

Stepping away from her was as hard as wrapping a cord around his own neck and diving into fire.

"No, no, _please_ ," she whined, reaching for him with her free hand, the other still at work between her legs. "I'll do anything you want — I'll _pay you_ , just fuck me, please, please fuck me!"

John took a deep, shuddering breath and closed his eyes. He couldn't bring himself to say _no_ , but his conscience wouldn't let him say yes, either.

He was a doctor. He could find a way to help her.

"Do you have a boyfriend— a partner?" he asked, trying to breathe through his mouth, to smell her as little as possible. It didn't help much.

She whined and shook her head, rolling it against the door as though she couldn't even control that movement.

He swallowed. It seemed like he was salivating much more than usual, and he was sure his pants were damp with pre-come. "Get into your room. I'll make sure you get what you need, I promise, but you need to get out of the hallway first."

It took a little more urging to get her to fumble for her room key and slip inside, largely verbal; John didn't trust himself to touch her much, but she needed a nudge here, and a push there. When her door clicked shut, a relieved, unhappy void filled the space where she'd been. Past his regret, John knew it was for the best. He could still smell her, still wanted her, but he was getting more clear-headed, more aware that he'd made the right decision. He could only hope no other alphas would pass by soon.

Back in his own room, he called the front desk.

"This is going to sound a bit unusual," he said, but the voice on the other side said no. Apparently ordering sex toys like room service was rapidly becoming commonplace.

He had it charged to his own room, reminding them before he hung up to have the toys delivered by a beta or an omega — needlessly, probably, as they seemed familiar enough with the situation, but he felt better having said it, and he was hardly in his right mind yet anyway.

His cock was still achingly hard.

The woman's smell was only a faint memory by the time he shoved his pants down, and the moment he touched himself a different memory replaced it: Sherlock on his hands and knees, pushing back onto John's cock and begging for it; Sherlock's arse, leaking come and slick fluids; Sherlock's eyes, looking to John like he was the solution to all the world's most difficult questions.

Sherlock, smirking and proud after a successful case, or tired and hungry after a difficult one, or sniping inappropriately at whatever irritated him when there weren't any cases at all.

Sherlock, just as he'd always been.

It felt wrong to even think of him that way without his permission. Sherlock might never know, or might already assume John was doing it, but he couldn't keep it up, not with the way his chest ached at the thought that he'd never get to chase a murderer through the streets or sneak up on a thief with him again.

Instead, John let his mind go blank, jerking himself off mechanically. Even with nothing to picture, he came in no time at all, and shortly thereafter closed his eyes and tried to let the day go.

He slept poorly.

* * *

The text came in the late afternoon on his second day at the hotel.

**Double homicide in Ealing. Corpses apparently burned from the inside out. This could take a while. Bring your things back to Baker Street first. SH**

It didn't even occur to John to do anything else. He was thankful he'd only brought the one bag; he couldn't get out onto the street and into a cab fast enough.

* * *

By the time John followed Sherlock back into their flat — still _their_ flat, thank god — he was utterly exhausted. There had been no running during the course of Sherlock's case, no kind of strenuous physical exertion at all. They hadn't stayed out late, either, not by their standards. In fact, in the long run of things, it was a mediocre case, one that might not even make the blog except that the murderer's motive had been particularly interesting: protecting a drug that was supposed to undo the effects of the dust, one that she'd rushed into highly illegal human trials, unable to predict the way it would make their reproductive organs shrivel and rot.

It was his own mind that made the day seem as long as two. Throughout the whole thing it had whirred, trying to absorb information at something like half the rate Sherlock's did. He'd watched the way Sherlock hardly looked at him, the way he only spoke to him out of the corner of his mouth unless John was looking away, and the way, at the end, Sherlock had tried to make a joke, to smile, even.

John had smiled back, but that was hardly the end of things, even if he'd left it for the time being.

There was no avoiding it in the flat, though. The flat was their cocoon, the scent of each of them and both of them saturated into its atmosphere, and it was tainted by their hostility and what had started only a week before in Sherlock's bed. It was unavoidable, coating the air like thick smog, like dust.

They hadn't eaten. John hadn't suggested it, afraid that if they stopped anywhere else they would avoid everything they needed to say and never get it out. He was uncomfortably hungry, but he ignored it, sitting in his chair and meeting Sherlock's eyes before the other man could look away.

"We're going to have to talk about it." He let his tone, the straight line of his mouth, brook no argument. It was rarely an effective method of convincing Sherlock of anything, but even he had to see that this particular discussion was important.

He did, sitting on the sofa, his elbows propped on his knees, fingers steepled in front of his face.

They were both silent for many long seconds.

John was mentally redrafting his opening line for the eighth time when Sherlock finally said, "I'm sorry I dragged you out into the dust."

John frowned. "Of everything that's happened, I'm pretty sure that's the least likely thing I'd have issue with. You haul me around the city all the time, and it's not like either of us would have stayed in anyway."

"You would have." Sherlock averted his eyes, huffed out a breath through his nose. "You'd have been cautious, if you had thought about it. You could have been normal, still."

"Sherlock, tell me you don't actually believe that."

Sherlock didn't look at him, didn't answer.

"All right, no, I _know_ you don't believe that. You probably know exactly how many people didn't have some exposure to the dust, and how many people didn't react to it if they would have. I'll bet those numbers are close to nothing. I saw plenty of people who didn't change at all wiping that stuff off their clothes at the clinic, and plenty more who did change and claimed they were careful about avoiding contact with it."

"You could have changed more slowly," Sherlock said, sharp and frustrated. He tilted his head toward John, but kept his eyes turned away. "You could have been normal for longer. There's proof for that, at least."

John almost wanted to laugh; he'd never thought he'd see the day when Sherlock would argue that he _was_ guilty of something out of his control. It seemed completely absurd. "What difference would it have made? I'd still be like this, and you the way you are. Neither of us would have been any better off, in the end. Maybe I'd have just been in denial longer."

There was another silence, and after a few moments, Sherlock gave a low hum. John figured that was about all the agreement he'd get out of him just then.

He wanted to reach out, to touch and reassure Sherlock, but he was afraid to, irrationally. He knew touching would stimulate little now, and that Sherlock wasn't about to mistake that for anything more, but he couldn't will his arm to move. He felt foolish and ashamed at not being able to offer his friend comfort, but there wasn't anything for it.

When Sherlock spoke again, it was so abrupt John nearly jumped. "I enjoyed it."

He didn't hear right. He couldn't have. "Sorry?"

And then Sherlock was meeting his eyes again, finally, looking vicious and sick and pleading. "I liked it. Too much, and not— not the way I would have if that man in the alley had fucked me instead, I don't think. I _hate_ that I liked it."

John leaned forward. If he couldn't offer touch, he could at least offer his presence. "I'm sorry I did that to you, but— it's just biology, you know, physiological responses to stimuli—"

" _Fuck_ physiology." Sherlock jumped up so fast John tilted back into his chair, looking up at him as he paced. "It's been years since I cared about the size of anyone's cock, and I didn't care about yours, either. I can't stop thinking about it, now. It feels like I've wasted time, and that's even worse, but I'm not sure if it's because I hate wasting time or if it's because I hate wanting you to fuck me even when I don't have the excuse of an excessive amount of pheromones leaking out of me. I hate that you only go for women, and I'm thankful for it, because if you didn't I'd do something impossibly stupid. I've thought about _kissing_ you while you've been away."

John felt cold and warm in turns as Sherlock spoke, unsure if he should apologise or be offended, if the sudden, insane urge to let Sherlock kiss him — or to take the initiative and do it himself — was all about pity or just something that had been altered in him.

At least, he was fairly certain he hadn't wanted to kiss Sherlock before. He wasn't even entirely sure if it was a want at all, or if it was just one of those ideas that got stuck in the brain and looked like something one should want.

There wasn't time to figure it out. Or — yes, there was time, of course there was, but letting it slip by felt like a retreat, like denial. It would be the sensible thing to do, to think about it and be sure of what he wanted before he said anything.

Things with Sherlock were rarely sensible. Life at 221B Baker Street preferred logic over sensibility. 

He reached out and grasped Sherlock's arm, just above his wrist, as he paced by. "Do it then."

It was the logical thing to do.

"We won't know how we feel about it until we've tried."

It wasn't logical at all, not really, but Sherlock didn't point that out — for once. He hesitated only a moment before bending down rigidly. John had to tilt his head up, push off the chair a bit to meet him.

It was chaste, dry and warm. It wasn't special, or particularly different from other kisses John had had. It wasn't anything.

It made him think, _Yeah, I could do this._

Evidently something inside him had been altered after all, because he reached up and grabbed a fistful of hair and even though Sherlock didn't smell like much at all, he wanted him.

* * *

A second wave of dust became visible in the skies over London on a night in early March, the air still cold, but carrying the promise of spring.

John didn't notice it; he was too busy panicking, laying back on Sherlock's bed, naked and hard. His fingers were clawed into the bedding, keeping him grounded. He felt dizzy even though he wasn't upright, and he was suffering from his thousandth wave of doubt.

God, what was he doing?

He was going out of his mind, obviously. He was watching Sherlock stick his fingers up into himself, slippery this time with lubricant bought from a shop. He was waiting to fuck Sherlock Holmes.

He thought that if he could go back in time, back before November, and describe the scene to his earlier self, he'd have got a black eye for his trouble. He wasn't _gay_. He didn't have a cock with a knot, and he wanted nothing to do with Sherlock's arse.

Except he did. Oh, god, he did.

He'd had sixteen days to come to terms with it, and it still seemed so unreal. Unreal that Sherlock could want him, or anybody at all, and that he could want him back, just as himself and not some lust-crazed beast. He still thought that beast played some part in it, but he wasn't sure it mattered. It would work. If he could kiss Sherlock, if he could fuck him, if he could _want_ to fuck him, there wasn't any reason not to, not when he adored everything else about him.

Almost everything else. All the important things, anyway.

Another rush of panic ran through him, and he entertained the half-crazed thought of running, even if he was naked and stiff as a pole. He could blame it on the hormones. He could—

He could watch, nearly in awe, as Sherlock took him in hand, knelt over him, and sank down, hot and tight and not at all like he had been before, right onto his cock.

He could groan, because it felt far too good.

He put his hands on Sherlock's hips, only to have them pushed down to the bed, kept there by unforgiving fingers. He met Sherlock's eyes, too blown away to be worried by the fierce look in them.

"I control this," Sherlock said, pressing his hands down. He held John's right hand at the wrist, but tangled the fingers of their other hands together. "I think you'll find we'll both enjoy it better this way."

John wasn't sure, but he kept still as Sherlock rose up and sank back down, as his nipples were pinched and his ears were bitten. He didn't keep still when he was kissed, but he let himself be held down, invaded, and Sherlock forgave him.

Later, they would have to negotiate sleeping arrangements. John would have to come to terms with Sherlock continuing to be lazy at times, manic at others, and always socially inept; Sherlock would have to re-learn how to navigate the seas of a sexual and possibly romantic relationship.

It was all terrifying, completely and utterly, to the both of them, but as the rain started and drowned out the sounds of their bodies coming together, they both wanted it terribly, and without any help at all.

**Works inspired by this one:**

  * [DUSTFALL](https://archiveofourown.org/works/4953442) by [LizDe_Chan](https://archiveofourown.org/users/LizDe_Chan/pseuds/LizDe_Chan)




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